CN114274542A - LCP film and preparation method and application thereof - Google Patents
LCP film and preparation method and application thereof Download PDFInfo
- Publication number
- CN114274542A CN114274542A CN202111394676.XA CN202111394676A CN114274542A CN 114274542 A CN114274542 A CN 114274542A CN 202111394676 A CN202111394676 A CN 202111394676A CN 114274542 A CN114274542 A CN 114274542A
- Authority
- CN
- China
- Prior art keywords
- film
- lcp
- bubble
- lcp film
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention discloses an LCP film and a preparation method and application thereof. The LCP film preparation method adopts an extrusion blow molding method, and requires that the stretching rate of LCP resin melt measured at a certain temperature is 0.1s‑1Time and stretching rate of 10s‑1The elongational viscosity and the elongational viscosity activation energy are in a certain range, and the blow molding temperature of the LCP film (the bubble temperature T at the position where the bubble is 100mm away from the die outlet along the axial direction) is controllednIs Tm‑10℃~Tm+20 deg.c, the thickness uniformity deviation of the prepared LCP film is less than 10%, and the surface of the film has wrinklesThe method has less defects and good isotropy in mechanical property, effectively solves the problems that the LCP film prepared by the existing extrusion blow molding method is easy to generate wrinkles and the uniformity of the thickness of the film is poor, and is beneficial to the subsequent application of the film.
Description
Technical Field
The invention relates to the technical field of film production and processing, in particular to an LCP film and a preparation method and application thereof.
Background
The Liquid Crystal Polymer (LCP) has excellent high-frequency dielectric property, processing fluidity, high heat resistance and dimensional stability, and has very wide application in the field of electronic and electric appliances. The 5G commercial era shows higher electromagnetic wave transmission speed and smaller signal propagation loss, and the dielectric constant and the dielectric loss of the material are required to be as small as possible, and the liquid crystal polymer is the material meeting the strict requirements. Therefore, flexible printed circuit boards (FPCs) based on LCP films are the best material for 5G terminal antennas.
The prior art generally uses extrusion blow molding to produce LCP films. However, after the LCP melt is extruded from the annular die, the film bubble has poor stability, and during the blow molding process, the film bubble is prone to shaking, which causes the formed blown film to wrinkle easily, and also causes the problems of poor film thickness uniformity and mechanical property anisotropy, which affects the subsequent application of the film, and seriously reduces the market value of the LCP film.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a preparation method of an LCP film, and the prepared LCP film has few surface wrinkles, uniform thickness and good isotropy in mechanical property.
The invention is realized by the following technical scheme:
a method for preparing LCP film, comprising the following steps: the LCP resin is melted and plasticized by an extruder, extruded through a die to form a film bubble, a gas medium is introduced into the film bubble to blow the film bubble, the film bubble is cooled and shaped by an air ring, the film bubble is flattened and clamped after reaching a herringbone plate, and the film bubble is pulled out by a guide roller to be rolled and formed to prepare the LCP film;
the LCP resin melt is at TmThe draw rate measured at +20 ℃ was 10s-1Extensional viscosity η ofeNot less than 4000 Pa · s; at Tm~TmThe tensile rate measured at +30 ℃ was 0.1s-1Extensional viscosity activation energy Ea1At 35-45kJ/mol and a drawing rate of 10s-1Extensional viscosity activation energy Ea2Is 55-80kJ/mol, and Ea2/ Ea11.4 to 1.9;
the temperature T of the film bubble at the position of 100mm of the film bubble from the outlet of the die along the axial directionnIs Tm-10℃~Tm+20℃；
Wherein, T ismThe melting point of the LCP resin.
The invention requires that the temperature of the film bubble at the position of 100mm axial distance from the outlet of the mouth mold is in a certain range, namely the blow molding temperature of the LCP film is controlled, when the melt of the film bubble is in the temperature range required by the invention, a gas medium is introduced into the film bubble to ensure that the tubular film bubble is blown up, and the melt of the film bubble has higher extensional viscosity, so that the problems of serious surface wrinkles of the film or poor uniformity of the thickness of the film and the like caused by the rupture or deflection of the film bubble can be effectively avoided. Preferably, the bubble temperature T of the bubble at a position 100mm axially away from the die outletnIs Tm-5℃~Tm+15 ℃; more preferably, the bubble temperature T is at a position where the bubble is located at an axial distance of 100mm from the die exitnIs Tm~Tm+10℃ 。
In the extrusion blow molding process, when LCP melt is extruded from a die, the development process of the film bubble has almost no shearing behavior but mainly shows stretching behavior, only a stretching force field but no shearing force field is applied to the surface of the melt of the film bubble, and the stretching rate in the MD direction (namely the axial direction) is gradually reduced from the maximum value along with the increase of the axial distanceThe stretching rate in the TD direction (i.e., transverse direction) is increased to a maximum value and then decreased; generally, the external drawing force field applies a draw rate in the range of 0.1 to 10 seconds after the bubble melt exits the die-1In the meantime. When the film bubble leaves the die and develops along the axial direction, the stretching speed in the MD direction is instantaneously increased to the maximum, in order to avoid the phenomenon that the stretching viscosity of the melt of the film bubble is rapidly reduced to cause the film bubble to start shaking, the stretching viscosity of the melt can be obviously increased along with the reduction of the temperature at the stretching speed, namely the stretching viscosity activation energy is larger; and after the bubble crosses the highest point of the hanging neck line of the film tube (the axial distance from the highest point of the thin neck line of the bubble to the outlet of the neck mold), the bubble begins to be blown along the TD direction, the stretching speed of the melt along the TD direction begins to increase, and in order to ensure that the bubble can be easily blown and has better thickness uniformity, the stretching viscosity of the melt cannot be obviously increased along with the reduction of the temperature under the stretching speed, namely the stretching viscosity activation energy is smaller. The invention requires the maximum stretching speed of 10s under the action of the external stretching force field-1And minimum draw rate of 0.1s-1And the tensile viscosity activation energy of the LCP resin melt is in a certain range, so that the LCP film with uniform thickness, smooth surface and few wrinkles can be prepared.
The extensional viscosity of the present invention can be measured by using a rheometer.
The invention provides a test method of the extensional viscosity activation energy, which comprises the following steps:
at a temperature Tm~TmSelecting at least 3 different temperatures within +30 deg.C, and measuring the stretching rate with a rotary rheometer at 0.1s-1The elongational viscosity of the resin melt at different temperatures is combined with the Arrhenius equation to obtain the activation energy Ea of the elongational viscosity1(ii) a The stretching rate is measured to be 10s by adopting a capillary rheometer and selecting a stretching Cogswell method-1The elongational viscosity of the resin melt at different temperatures is combined with the Arrhenius equation to obtain the activation energy Ea of the elongational viscosity2。
Preferably, the LCP resin is selected from thermotropic liquid crystal polymers with the melting point of 250-350 ℃.
Preferably, the invention adopts the blow molding conditions that the bubble stretch ratio is 2-10 and the blow-up ratio is 3-8 to prepare the LCP film with the thickness of 10-200 mu m.
Preferably, the barrel temperature of the extruder is 240-310 ℃.
Preferably, the gas medium can be selected from air, nitrogen or carbon dioxide. For cost reasons, air is more preferred as the gaseous medium for film blowing in industrial processes.
The invention also provides the LCP film prepared by the preparation method.
The thickness of the LCP film is 10-200 mu m; preferably, the thickness of the LCP film is 15-100 mu m.
The deviation of the thickness uniformity of the LCP film is less than 10 percent.
The LCP film is continuously rolled by 300m, and the number of surface wrinkles is less than 15.
The invention also provides application of the LCP film, which can be used for 5G mobile terminals, 5G communication radars or antennas of 5G base stations.
Compared with the prior art, the invention has the following beneficial effects:
the preparation method of the invention requires that the tensile rate of LCP resin melt measured at a certain temperature is 0.1s-1Time and stretching rate of 10s-1The stretching viscosity and the activation energy of the stretching viscosity are in a certain range, the blow molding temperature of the LCP film is controlled at the same time (the temperature of the film bubble when the axial distance of the film bubble from an outlet of a neck mold is 100mm is required to be in a certain range), the thickness of the prepared LCP film is uniform (the deviation of the thickness uniformity is less than 10%), the surface quality of the film is high (300 m is continuously rolled, the number of surface wrinkles is less than 15), the mechanical property is good in isotropy, the problems that the existing extrusion blow molding method for preparing the LCP film easily generates wrinkles and the uniformity of the film thickness is poor are effectively solved, and the subsequent application of the film is facilitated.
Drawings
FIG. 1 is a schematic view of a part of the structure of an LCP film extrusion blow molding apparatus; 1 is a film bubble; 2 is a herringbone plate; 3 is a wind ring; and 4, a die.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way.
The LCP films of the examples and comparative examples of the present invention were prepared by the following methods: the method comprises the steps of adopting equipment shown in figure 1, melting and plasticizing LCP resin by an extruder, extruding the melted and plasticized LCP resin through a die 4 to form a film bubble 1, introducing a gas medium into the film bubble to blow the film bubble, cooling and shaping the film bubble through an air ring 3, flattening and flattening the film bubble after the film bubble reaches a herringbone plate 2, drawing out the film bubble through a guide roller, and rolling and forming to obtain the LCP film. Physical properties of the LCP resins used in the examples and comparative examples and blow molding conditions of the LCP films are shown in Table 1/Table 3.
In the examples and comparative examples of the present invention, thermotropic liquid crystalline polymers having melting points of 250-350 ℃ were selected for the LCP resin, and the physical properties (melting point, extensional viscosity, and extensional viscosity activation energy) of the LCP resin were measured by the following methods:
(1) determination of melting point of LCP resin: a differential scanning calorimeter DSC 200F 3 manufactured by NETZSCH company is adopted, the temperature rising rate is 20 ℃/min, the temperature is raised to be 30 ℃ above the melting point, the temperature is kept for 5min, then the temperature is lowered to the room temperature at 20 ℃/min, the temperature is raised to be 30 ℃ above the melting point at 20 ℃/min, and the temperature corresponding to the melting peak value of the curve of the second temperature rise is taken as the melting point of the LCP resin.
(2) Determination of elongational viscosity and elongational viscosity activation energy of LCP resin melt:
at a temperature Tm+10℃、Tm+20℃、TmThe strain rate was measured at +30 ℃ using a rotational rheometer to be 0.1s-1The extensional viscosity of the resin melt; the strain rate was measured for 10s using a two-barrel capillary rheometer (using a long die with an internal diameter of 1mm and a length of 20mm and a short die with an internal diameter of 1mm and a length of 0.25 mm) using a tensile Cogswell method-1The extensional viscosity of the resin melt; combining with Arrhenius equation to obtain the stretching rate of 0.1s-1Extensional viscosity activation energy Ea1And a drawing rate of 10s-1Extensional viscosity activation energy Ea2(ii) a Recording T simultaneouslymA stretching rate at a temperature of +20 ℃ of10s-1The extensional viscosity eta of the resin melte。
In the examples of the present invention and comparative examples, the LCP films prepared were evaluated by the following methods:
(1) film thickness: the thickness of the LCP film was measured by a digital thickness meter (Mitutoy Co., Ltd.) at intervals of 0.05m in the TD and MD directions.
Respectively taking 3 different positions every 1m along the MD direction, respectively measuring the positions at intervals of 0.05m along the TD direction, measuring the film thickness of 30 points in total, and randomly selecting the average value of 10 points to be set as the average film thickness in the TD direction; the thickness uniformity deviation R was calculated by taking the maximum value of the obtained 30-point measurement values as Lmax, the minimum value as Lmin, and the average value as La: r = (Lmax-Lmin)/2 La;
taking 3 different positions at intervals of 0.15m along the TD direction, respectively measuring at intervals of 0.05m along the MD direction, measuring the film thickness of 30 points in total, and optionally selecting the average value of 10 points to be set as the average film thickness in the MD direction; the thickness uniformity deviation R was calculated by taking the maximum value of the obtained 30-point measurement values as Lmax, the minimum value as Lmin, and the average value as La: r = (Lmax-Lmin)/2 La;
the "R is less than 7%" is excellent, the "R is more than or equal to 7%" is good, and the "R is more than or equal to 10%" is unqualified.
(2) Evaluation of film surface wrinkles: the length of the film is observed by naked eyes within 300m, and the number of wrinkles on the surface of the film is used as a judgment basis. The number of wrinkles of 0. ltoreq.8 was evaluated as excellent, the number of wrinkles of 8. ltoreq.15 was evaluated as good, the number of wrinkles of 15. ltoreq.30 was evaluated as acceptable, and the number of wrinkles of > 30 was evaluated as poor.
(3) Tensile strength of the film:
adopting an ASTM D882-18 method, cutting a 10mm multiplied by 15cm sample strip from the film, measuring by using Shenzhen Sansi universal tensile test equipment, wherein the tensile speed is 10mm/min, and measuring to obtain MD tensile strength and TD tensile strength; the MD/TD tensile strength is less than 1.7, which shows that the film has better isotropy of mechanical properties.
Table 1: physical Properties of LCP resins used in examples 1 to 8 and conditions for blow Molding of LCP films
Table 2: evaluation results of LCP films obtained in examples 1 to 8
Table 3: physical Properties of LCP resins used in comparative examples 1 to 6 and conditions for blow Molding of LCP films
Table 4: evaluation results of LCP films obtained in comparative examples 1 to 6
As is apparent from the above examples and comparative examples, the preparation method of the present invention requires that the LCP resin melt have a draw rate of 0.1s as measured at a certain temperature-1Time and stretching rate of 10s-1The activation energy of the stretching viscosity is in a certain range, the blow molding temperature of the LCP film is controlled (the temperature of the film bubble is in a certain range when the distance between the film bubble and the outlet of the neck mold along the axial direction is 100 mm), the prepared LCP film has uniform thickness (the deviation of the thickness uniformity is less than 10 percent), few surface wrinkles (the thickness uniformity is 300m in continuous rolling, the number of the surface wrinkles is less than 15), and the tensile strength MD/TD of the film<1.7, has good isotropy of mechanical properties.
Claims (9)
1. A method for preparing LCP film, which is characterized by comprising the following steps: the LCP resin is melted and plasticized by an extruder, extruded through a die to form a film bubble, a gas medium is introduced into the film bubble to blow the film bubble, the film bubble is cooled and shaped by an air ring, the film bubble is flattened and clamped after reaching a herringbone plate, and the film bubble is pulled out by a guide roller to be rolled and formed to prepare the LCP film;
the LCP resin melt is at TmThe draw rate measured at +20 ℃ was 10s-1Extensional viscosity η ofeNot less than 4000 Pa · s; at Tm~TmThe tensile rate measured at +30 ℃ was 0.1s-1Extensional viscosity activation energy Ea1At 35-45kJ/mol and a drawing rate of 10s-1Extensional viscosity activation energy Ea2Is 55-80kJ/mol, and Ea2/ Ea11.4 to 1.9;
the temperature T of the film bubble at the position of 100mm of the film bubble from the outlet of the die along the axial directionnIs Tm-10℃~Tm+20℃；
Wherein, T ismThe melting point of the LCP resin.
2. The method for preparing an LCP film according to claim 1, wherein the temperature T of the bubble is 100mm axially away from the die exitnIs Tm-5℃~Tm+15 ℃; preferably, the bubble temperature T of the bubble at a position 100mm axially away from the die outletnIs Tm~Tm+10℃。
3. The method as claimed in claim 1, wherein the LCP resin is selected from thermotropic liquid crystal polymers with melting point of 250-350 ℃.
4. The method of claim 1, wherein the blowing conditions are 2-10 bubble stretch ratio and 3-8 blow ratio.
5. An LCP film produced by the production method according to any one of claims 1 to 4.
6. The LCP film according to claim 5, wherein the LCP film has a thickness of 10-200 μm; preferably, the thickness of the LCP film is 15-100 mu m.
7. The LCP film of claim 5, wherein the thickness uniformity of the LCP film has a deviation of less than 10%.
8. The LCP film of claim 5, wherein the LCP film is continuously rolled up to 300m, and the number of surface folds is less than 15.
9. Use of the LCP film of any one of claims 5 to 8 for antennas for 5G mobile terminals, 5G communication radars or 5G base stations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111394676.XA CN114274542A (en) | 2021-11-23 | 2021-11-23 | LCP film and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111394676.XA CN114274542A (en) | 2021-11-23 | 2021-11-23 | LCP film and preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114274542A true CN114274542A (en) | 2022-04-05 |
Family
ID=80869769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111394676.XA Pending CN114274542A (en) | 2021-11-23 | 2021-11-23 | LCP film and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114274542A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000326405A (en) * | 1999-05-18 | 2000-11-28 | Kuraray Co Ltd | Production of film from thermoplastic liquid crystal polymer |
| US20040232603A1 (en) * | 2003-05-21 | 2004-11-25 | Kuraray Co., Ltd. | Film forming method |
| CN113400611A (en) * | 2021-06-18 | 2021-09-17 | 宁波长阳科技股份有限公司 | Film blow molding device and liquid crystal polymer film prepared by same |
-
2021
- 2021-11-23 CN CN202111394676.XA patent/CN114274542A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000326405A (en) * | 1999-05-18 | 2000-11-28 | Kuraray Co Ltd | Production of film from thermoplastic liquid crystal polymer |
| US20040232603A1 (en) * | 2003-05-21 | 2004-11-25 | Kuraray Co., Ltd. | Film forming method |
| CN113400611A (en) * | 2021-06-18 | 2021-09-17 | 宁波长阳科技股份有限公司 | Film blow molding device and liquid crystal polymer film prepared by same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113400611B (en) | Film blow molding device and liquid crystal polymer film prepared by same | |
| CN103522552A (en) | Fluorine-containing thin film tape casting preparing method | |
| JP2015080917A (en) | Method and apparatus for producing polyether ketone resin film | |
| CN112759776A (en) | Polyarylester modified liquid crystal polymer film and preparation method thereof | |
| CN112549475A (en) | Method and device for preparing liquid crystal polymer film | |
| WO2024055972A1 (en) | Lcp resin composition, preparation method therefor, and use thereof | |
| CN112571776B (en) | Film blowing device for realizing transverse blowing of liquid crystal polymer and preparation method | |
| JP2017103724A (en) | Method for manufacturing film for vibration plate of speaker | |
| CN114274542A (en) | LCP film and preparation method and application thereof | |
| CN114274541B (en) | LCP film and preparation method and application thereof | |
| JP2014051682A (en) | Polyolefin-based resin foamed sheet | |
| JPH0733048B2 (en) | Method for producing polybutylene terephthalate resin film | |
| JP4679679B2 (en) | Method for producing thermoplastic liquid crystal polymer film | |
| CN114685963B (en) | TLCP material, preparation method thereof and TLCP film prepared from TLCP material | |
| CN113088020B (en) | Easily-torn thermoplastic polyvinyl alcohol film and preparation method and application thereof | |
| CN104149327A (en) | Secondary blow molding method of polylactic acid film | |
| CN114248414A (en) | Film blow molding device and liquid crystal polymer film prepared by same | |
| JPH0314840A (en) | Biaxially cold-stretched vinylidene fluoride polymer film and its preparation | |
| CN112440460A (en) | Forming system and method for functional high polymer material in blown film processing | |
| JPH0250817A (en) | Method and device for manufacturing plastic continuum | |
| CN117863537A (en) | Secondary inflation preparation method of LCP film and special equipment thereof | |
| CN111261404B (en) | Preparation method of synchronous-stretching polypropylene high-temperature-resistant film for wireless charging | |
| WO2024075636A1 (en) | Method for producing thermoplastic liquid crystal polymer film | |
| CN114156020A (en) | Audio and video cable with physical foaming core wire diameter smaller than 1.8mm and preparation process thereof | |
| CN214324171U (en) | A molding system for blown film processing functional macromolecular material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |